Effects of salinity, food level and temperature on the

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Title
Effects of salinity, food level and temperature on the population growth on
Noctiluca scintillans (Macarthy)
Author(s)
Lee, Jung Keun; Hirayama, Kazutsugu
Citation
長崎大学水産学部研究報告, v.71, pp.163-168; 1992
Issue Date
1992-03
URL
http://hdl.handle.net/10069/29863
Right
This document is downloaded at: 2015-02-01T05:32:56Z
http://naosite.lb.nagasaki-u.ac.jp
Bull. Fac. Fish. Nagasaki
Effects
163
Univ., No. 71 (1992)
of salinity,
population
food level and temperature
growth
of Noctiluca
scintillans
Jung Keun LEE* and Kazutsugu
The population
tetrathelle
cells/ml
(Macartney).
HIRAYAMA
growth of Noctiluca scintillans was investigated,
using Tetraselmis
as food, at salinities ranging from 8.5-34‰, food levels from 1 x 10³-8 × 105
and temperatues
from 5-32°C. Under every experimental
twenty Noctiluca were grown individually
to four days.
analysis
on the
The specific growth
of the population
condition,
in 1 or 3m1 of food suspensions
rates were obtained
ten to
for three
from the linear regression
growth.
Salinity : The specific growth rate was maximal at approximately
22‰, and
decreased differentially with increasing or decreasing salinities. The lowest salinity
for the minimal
and continual
growth was 14%o, but the sudden
drop from 34‰ to
14‰ was lethal.
Food Level : There was little growth at the food levels lower than 3 ×104 cells/
ml. At food levels between 3x 104and 3x 105cells/ml, the specific growth rate increased
proportionally
rate increased
with increasing
asymptotically.
D ; 0.16) at 3 × 104 cells/ml,
food levels. With further increases in food level, the
The values of the specific growth rates were 0.03 (S.
0.74 (S. D ; 0.16) at 3 x 105 cells/ml
at 8 ×105 cells/ml.
Temperature : The specific growth rate was maximal
around 23°C, and decreased
differentially with increasing or decreasing temperatures.
°C
within a day. It grew at 5°C normally but slowly.
Key words :
A marine
widely
the
protist
distributed
arctic.'
growth
Noctiluca
from
the
caused
frequently
and tropical
by
reported
from
many
In Japan,
the Noctiluca
almost
annually
between
depending
on the year
frequency
between
factors
In
red tide
and
in
the
have
and site."
of occurrance,
its growth
and
parts
spring
is
to the
plankton
density
world.
its
scintillans
seas,
its high
rate ; Noctiluca
tropics'
It is one of the dominant
temperate
tides
specific
red
been
elucidate
this information,
experiments
of
are
necessary
and a stable
Noctiluca
*
School
Science
culture
Engineering.
phytoflagellate
6) We found
that
in the prelimi-
Tetraselmis
for Noctiluca,
Noctiluca
culture
ly in 1 or 3m1 of food suspensions
lationship
to
in an organically
in the
tetrathelle
and could
using
this
In this study, we grew Noctiluca individual-
experimental
cultures
and
a stable
tetrathelle;
both
and
has a high food value
the basic
is a prerequsite.
of Marine
nary
food organism.
relationship
of Noctiluca
Graduate
food suspension.'
occurs
autumn
and the basic environmental
experiments
conducted
medium'
establish
are not well known.
vitro
Tetraselmis
been
enriched
All Noctiluca died at 32
of the
In spite
the
scintillans;
have
and 0.81 (S. D ; 0.12)
conditions
between
and
under various
clarified
its population
environmental
factors.
the
growth
reand
164
LEE and HiRAyAMA ： Growth of Noctiluca
Materials and Methods
cycle． Sixty Noctiluca from each acclimated
culture were tested in six salinities． ten Noctiluca
’
Al∂ctilzaca was collected with a plankton net
in each salinity． Only those with active tentacle
from Nomozaki Bay in Nagasaki Prefecture，
movement were used． They were placed indi−
southern Japan． It was maintained in culture
vidually in 3ml of food suspensions of various
on a diet of T． tetrathe〃e in about 100rnl of
salinities， and their growth was monitored for
GF／C filtered seaWater in petri−dishes． The
three days． The food suspension was pre−
むロ
culture was carrled out at 22−23 C ln fluorescent
pared by adding lml of food culture （about 3×
light（（2−4）×1031ux）on 14L：10D light cycle．
105 cells／ml） to 2ml of filtered sea water of the
，
To deter面ne the s．pecific growth rate under
same salinity， and its resultant concentration
each experimental condition， ten to twenty
was about 1×105 cells／ml．
〈ioctiluca were grown individually in l or 3ml
b． lnfluence of salinity on the stoutness of
of conditioned food suspensions for three to
Noctiluca
four days． This corresponded to ten to twenty
Noctiluca were separatey cultured at 23， 28
cases． The experimental vessels used were
and 320／oo for three weeks with sufficient food
’
Falcon multiplates（＃3046 for 3ml experiment，
and those with food vacuoles filled with algal
＃3047for lml experiment）， which were com−
food were used in the experiment． Thirty
pletely sealed with vinyl tape to prevent
IVoctiluca from each cultute were ’transferred
evaporation． Linear regression analysis was
into the wells of Falcon ＃ rr！ultiplate， five in
performed for each case using daily sensus
each well containing 3ml of filtered sea water．
counts， from which the following equation was
The multiplates were placed on an electric
deduced：
shaker which reciprocated a distance of 1．5cm
1n Nt＝kt十a
at a rate of 155 times／min． ’Shaking was
where Nt is the number of 1＞Octiluca at time t，
continued for periods of O， 2， 4， 8， 14， and 24
kis the specific growth rate， t is the time passed
hours， and surviving Noctiluca were counted 24
in days and a is constant． When gametocytes7）
hours after the start of shaking．
were formed（0−3 cases out of ten）， the cases
were excluded from the analysis． As many
2． Food level
specific growth rates as the valid cases were
The algal food used for the experiments，
obtained and the mean“k”with standard
Ti tetrathelle， was grown in diluted filtered sea
deviation， represented the specific growth rate
water （220／oo） enriched with Erd−Schreiber medium
under each experirnental condition．
（1 ： 1， volumetrically） to a concentration of 3×
1．Salinity
were obtained by diluting the food culture with
a．Specific growth rates
the diluted filtered sea water． Plankton cell
Noctiluca cultures were grown at four
countings were done on the food culture using
，
105 cells／ml． Various levels of food suspension
salinities（17，22，27 and 34％・）for more than a
a haemacytometer and the concentration was
week． T． tetrathelle were grown in six salinities
determined as the average of ten cell counts．
（10，14，17，22，27，and 34％・）， each in 100ml of
Noctiluca were cultured with sufficient food． and
’
Erd−Schreiber medium in a 200ml flask． The
those were used whose food−vacuoles were filled
salinity of‡iltered sea water was measured with
up with algal food． This experiment was run
a digital salinometer（Tsurumi seiki， E−202）， and
at 230C， 220／oo and in dim light． The specific
the desired salinities were obtained by diluting
growth rate at each food level was obtained by
filtered sea water with distilled water． The
growing ten IVoctiluca individually in lml of food
suspensions for four days．
experiments were run at 23 C on 14L：10D light
165
Bull． Fac． Fish． Nagasaki Univ．， No． 71 （1992）
but growth curve diverged by food level from
3。Temperature
the second day onwards． Thus， the data from
peratures for one month， ranging from 5 to
the second day on were used in the analysis．
280C， in a multi−chamber incubator accurate
to±0．5 C． Food was given sufficiently． The
（17 Oloo）
algal food was also grown at the same tern−
enriched with Erd−Schreiber medium （1：1，
り
acclimated at 28 C．．The initial food levels were
arranged at about 3×105 cells／ml． This ex−
periment was conducted at 22％・on 12L：12D
light cycle． The specific growth rate at each
〈roctiluca individually for three days in lml of
O・2
o
一〇．2
一〇4
（22 o／．）
4 2
0 0
temperature was obtained by growing twenty
O・4
0
一
and．at 32。C． Those tested at 32℃had been
︵z鑑，召︶ ”︵工︶田トくにエトタOαO 0一比一り国∩［の
food， and tested at each acclimated temperature
嗣℃
whose food vacuoles were filled up with algal
2 o
。2
㏄ α
o0 02
peratures in diluted filtered sea water（22％・）
volumetrically）・一Those〈⑩漉1％6αwere chosen．．
／
O・6
ヨ
（27 Ol．）
一逓
Noctiluca were first acclimated at six tem−
food suspensions．
（34 01．）
／1太
／i＊i
04
O・2
’
，’
Fig． 1 shows the specific growth rates of
Noctiluca at various salinities． Regardless of
’
Results
o
o
de wh．Lu−一LLLLLL．L
10 20 30 10 20 30
SAUNITY （e／eo）
the acclimated salinities． Nocliluca demonstrat一
’
Fig． 1． The specific growth rates of N scintillans
ed the highest specific growth rates at 220／oo，
grown at various salinities． ln the paren−
and the rates decreased differentially with
theses are shown the salinities they were
acclimated at before being transferred into
increasing or decreasing salinities． The lowest
various salinities． Vertical lines indicate
salinity for the continual population growth was
standard deviations． The open circle on
ユ4％・，but the sudden drop from 34％・to 14％・was
the x−axis signifies that all Noctiluca died
at that salinity．（N；the number of八り6−
lethal． ln lower than 100／oo S， Noctiluca was not
tiluca：t； time in days： k； the specific
viable．
growth rate）
Fig． 2 shows the survived number after
’
increased， the number of surviving Noctiluca
decreased in all the groups and there were no
皿コ： 28脇
〔＝＝コ：35eA・ 2
“」
40
黶j
〇
一一一一一一一一一一一一一一一一一一一一一一一一一一一
c
20
o
幽凶
」＿一騨旧＿；」r＿剛r騨」一」＿＿＿■」一
〇 2 4 8 14
and exposed to various food levels． The high
experiment regardless of the initial food levels，
二2
vl
．g
di ＝
Dい
E 一，一
the growth of Noctiluca， which were fully fed
growths were obtained in the first day of the
一： 22 ont
ゴOQ
the groups in tolerance to the shaking shock．
Fig． 3 is an example of the time course of
Acclimated satinity
60
一﹂σ緕
tendencies to indicate any differences among
αUロロΣ⊃Z ゴ］り
350／oo S， respectively． As the duration of shaking
︵0仁コσ￡oもﾐ醐い0‘一﹂Φζσ ω﹂‘“N︶
various lengths of shaking of three groups of
・Noctiluca which were acclimated at 22． 28 and
一
24
DURATION OF SHAKING （ hour）
Fig． 2．
The survival number of N． scintillans after
various Iengths of shaking．
166
LEE and HiRAyAMA ： Growth of IVoctiluca
8
／／e
；≦§メ…≡i羅7）
02
l一振
う
30
／e
i27・su
一
0
5
に国口Σ⊃Z ﹂﹂Uり
e／．／e（lo．11）
娼
↓
30
100
Q6
SaEinity：22 Oke
@ 鱗
e／
エト≧6配OQ一﹂［O国巳の
●（30ゆ32）
22『陶S
論1︶
︵Z潔
1・︵5山・く匡
23e c
20
十
α
︵
200
乏
so＋Z9
0
0
Fig． 5．
5 10 15 20 25 so
TEMPERATURE （eC）
The specific growth rates of N scintillans
grown at various temperatures． The num−
bers next to the vertical lines’ represent the
（丁）
food levels （cells ×10‘ ／ml） at the start and
end of the experiment． The explanation
10
o
Fig． 3．
The growth curves of N． scintillans which
were exposed to various food levels
104and 3×105 cells／m1， the specific growth rate
immediately after being fully fed． The
numbers in the parentheses indicate the
increased gradually with increasing food levels，
food levels （cells ×10‘／ml） at the start and
but it increased asymptotically with further
end of the experiment． For the food levels
increase in food level． The specific growth rateS
lower than 1×10‘ cells／ml， only the initial
（k）were O．03（S． D；0．16）at 3×104 cells／ml，0．74
（S．D；0．16）at 3×105 cells／ml and O．81（S． D；0．12）
at 8×105 cells／ml．
Fig．5shows the specific growth rates of
〈loctil勿ca at various temperatures． The rate was
む
highest around 23 C， and decreased differential−
十
十
エ↑≧O￠OO一﹂一〇国住の
O・2
十
︵
0 0
O・4
00 6
論︶杢︶ω↑く
︵Zメー−
23ec
22 9ke S
ー
ーエー
food levels are given．
LO
of marks is given in Fig． 1．
1 2 3 4
DAYS AFTER INOCULAT！ON
ly with increasing or decreasing temperatures．
む
八「octiluca grew at 5 C， but all died within a day
at、31−32 C． The food levels during the ex−
periment were between about 3×105 cells／ml
and about 5×105 cells／ml．
o
一〇一2
1 10 100
Discussion
FOOD LEVEL （cettsxlo4mt−t）
Fig． 4．
The specific growth rates of IV． scintillans
grown at various food levels． The ex−
planation of marks is given in Fig． 1．
The results in Fig． 1 demonstrate that
Noctilzaca is adaptable to wide range of salinities
when the salinity change is slow and gradual，
The growths of algal food during the experi−
and that the most suitable salinity for growth
ment under these experimental conditions were
of IVoctiluca is around 220／oo． The growth of
less than 200／o of the initial food levels．
algal food during the salinity experiment is
Fig． 4 shows the relationship between the
considered not to affect the results obtained
specific growth rate of Noctiluca and food level．
because T． tetrathelle is euryhaline and grows
There was little ，growth of Noctiluca at the food
at a similar rate in salinities ranging from 10
level lower than 3×104 cells／ml． Between 3×
to 340／oo．8’ The salinity at which the highest
167
Bull． Fac． Fish． Nagasaki Univ．， No．71 （1992）
growth rate is found is not necessarily the
be one of the causes of the disappearance．
optimal salinity for population increase． The
However， a tropical strain of green八ioctiluca，
physiological stoutness （i． e．， tolerance to the
which contains flagellated symbionts， grows well
adverse environment）must be considered as
around 300C．i） This indicates that the tolerance
well． The results in Fig．2show that〈loctilu ca
to high temperature may be different by strain．
grown at 22％・for three weeks is as phys−
Though八ioctiluca has a potential to grow
iologically stout as those grown at higher salini−
at a speed of more than one division a day， it
ties． From these results， it can be concluded
is highly improbable that such a high growth
that approximately 22％・is the optimal salinity
rate will be found in nature because the most
for ノ＞bctiluCa．
favorable environments （i． e．， 220／oo S， 220C and
Because the results of the salinity ex−
plenty of food） are hardly met at the same time．
periment showed that the optimal salinity for
The high salinity will always suppress the full
ノ＞Octiluca is 22％・， the food level experiment was
growth of Noctiluca， and it would be a rare case
carried out at 22％・， The results in Fig．3show
for them to meet even the threshold level of
that the growth of algal food during the ex−
living food， even during the spring time when
periment was suppressed enough under these
the phytoplankton flourish． Occasionally， the
experirnental conditions not to influence the
food organisms appear in high density， but
results obtained． The relationship between the
this state doesn’t last long． ln this respect， the
specific growth rate of Noctiluca and food level
bloom of Noctiluca seems to be a visual
drew a typical S−shaped growth curve（Fig．4）．
phenomenon which is not necessarily related
The maximal rate shows that， with enough food
to the sudden growth of it．
and a suitable environment 1＞Octiluca can divide
With respect to the maintenance and
more than twice a day． However， the fact that
increase of the Noctiluca population， the rela−
〈loctiluca started to grow around 3×104 cells／
で
tive importance of its tolerance to adverse
ml indicates that 1＞Octiluca in nature may be in
environments and its ability to use non−living
serious food deficient state as far as living food
organic matter as food source have yet to be
is concerned． This food deficient state seem
studied．
，
to be rectified by phagotrophy9）or possibly by
References
using dissolved organ！c matter4）， but the extent
of rectification has yet to be studied．
The results in Fig．5show thatハloctiluca
1） Sweeney， B． M．（1971）：Laboratory studies
is eurythermal and the optimal temperature is
of a green Noctiuca from New Guinea． J．
approximately 23 C． Based on the results of
phycol．， 7， 53−58．
food level experiments， this experiment was
2） Tibbs， J． F．（1967）： On some planktonic
done at the high food levels where the growth
protozoa taken from the track of drift
rate of Noctiluca increases asymptotically in
station ARLIS 1． 1960−1961． Arctic， 20， 247−
order that the varying food levels during the
254．
experiment would not affect the results ob一
3） Takayama， H．（1984）： Red tide organisms
tained． Noctiluca grows normally at 5 C to see
occurring in coastal waters of Hiroshima
the fact that they contained as much food in
prefecture−II： IVoctiluca scintillans （Macart−
their food vacuoles as those at higher
ney）．“ Bull． Hiroshima Fish． Res． Lab．， 14，
temperatures． In the temperate sea，〈loctiluca
25−29．
suddenly disappears in the summer season．10）
4） McGinn， M． P．（1962）： Axenic cultivation of
From the fact that all〈loctiluca died at 32。C，
Noctiluca scintillans． J． Protozool．， 16
the lethal effect of high temperature seems to
（suppl．）， 13．
168
LEE and
HIRAYAMA : Growth
Saibai Giken, 14 (2), 85-110.
5) Nawata, T., and T. Sibaoka (1976): Ionic
composition and pH of the vacuolar sap in
marine
dinoflagellate
of Noctiluca
9) Kimor, B. (1981) : The role of phagotrophic
Noctiluca. Plant Cell
dinoflagellates in marine ecosystems. 15.
European marine biology symposium. Kiel
Physiol. 17, 265-272.
6) Takayama, H. (1977): Culture of Noctiluca
(GRG) : lower organisms and their role in
the food web. Rheinheimer, G. ; Fluegel,
scintillans (Macartney).* Bull. Plankton Soc.
H. Lenz, Z. Zeitschel, B. (eds.). Institut
fuer Meereskunde, Kiel (FRG). 164-173.
Jap., 24 (2), 159-162.
7) Zingmark, R. G. (1970): Sexual reproduction
in the dinoflagellate
Noctiluca miliaris
10) Uhlig, G. and G. Sahling (1982): Rhythms
suriray. J. Phycol. 6, 122-126.
8) Okauchi,
and distributional
M. N. (1988) : The mass culture
and food value of Tetraselmis tetrathelle.**
夜光虫 (Notiluca
scintillans)
餌料密度,温
李
Tetraselmistetrathelleを
濁液に入れ,い
比増殖率を算出し,そ
in Noctiluca
の増殖と塩分,
度との関係
正根・平山
餌料として,10-20尾
ろいろの飼育条件で飼育し,そ
phenomena
miliaris. Ann. Inst. oceanogr., Paris, 58 (S),
277-284.
和次
の夜光虫を1尾
ずつ個別に1-3m1の
の増殖を調べた。3-4日
餌料懸
間の増殖経過から日間
の平均値を求めた。
塩分 (8.5-34‰) : 22‰ で最大の比増殖率が得られ,それ以上,それ以下の塩分では塩分の増
加あるいは減少とともに比増殖率は減少した。
が,
以上の塩分では安定的な増殖がみられた
34‰ の海水から直接 14‰ の海水に移すと死滅した。
餌料密度(1×10ｳ-8×105ce11s/ml):餌
んど増殖しなかった。3×IO4cells/mlか
に比増殖率も増加したが,そ
殖率の値 (22‰, 23C)
料密度が3×104cells/ml以
ら3×105cells/mlの
温度(5-32℃):最
れ以上の餌料密度では比増殖率の増加の割合は低下した。比増
大比増殖率は約23℃
あった。
でえられ,そ
の高温ではすべての夜光虫は1日
した。
* : in Japanese
** : in Japanese
光虫はほと
は3×104cells/mlで0.03/日(S.D.:0.16),3×105cells/mlで0.74
(S.D;0.16),8×105cells/mlで0.81/日(S.D.;0.12)で
少した。32℃
下では,夜
間では餌料密度の増加ととも
with English summary
れ以上,ま
たはそれ以下の温度では減
以内に死滅したが,5℃
の低温でも正常に増殖

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